Mercurial > touhou

comparison pytouhou/utils/bitstream.pyx @ 131:fab7ad2f0d8b

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Use Cython, improve performances!
author Thibaut Girka <thib@sitedethib.com>
date Sun, 11 Sep 2011 02:02:59 +0200
parents pytouhou/utils/bitstream.py@ac2e5e1c2c3c
children b5c7369abd7c
comparison
equal deleted inserted replaced
130:11ab06f4c4c6 131:fab7ad2f0d8b
1 # -*- encoding: utf-8 -*-
2 ##
3 ## Copyright (C) 2011 Thibaut Girka <thib@sitedethib.com>
4 ##
5 ## This program is free software; you can redistribute it and/or modify
6 ## it under the terms of the GNU General Public License as published
7 ## by the Free Software Foundation; version 3 only.
8 ##
9 ## This program is distributed in the hope that it will be useful,
10 ## but WITHOUT ANY WARRANTY; without even the implied warranty of
11 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 ## GNU General Public License for more details.
13 ##
14
15 cdef class BitStream:
16 cdef public io
17 cdef public int bits
18 cdef public int byte
19
20 def __init__(BitStream self, io):
21 self.io = io
22 self.bits = 0
23 self.byte = 0
24
25
26 def __enter__(self):
27 return self
28
29
30 def __exit__(self, type, value, traceback):
31 return self.io.__exit__(type, value, traceback)
32
33
34 def seek(BitStream self, offset, whence=0):
35 self.io.seek(offset, whence)
36 self.byte = 0
37 self.bits = 0
38
39
40 def tell(BitStream self):
41 return self.io.tell()
42
43
44 def tell2(BitStream self):
45 return self.io.tell(), self.bits
46
47
48 cpdef unsigned char read_bit(BitStream self):
49 if not self.bits:
50 self.byte = ord(self.io.read(1))
51 self.bits = 8
52 self.bits -= 1
53 return (self.byte >> self.bits) & 0x01
54
55
56 def read(BitStream self, nb_bits):
57 cdef unsigned int value
58 value = 0
59 for i in range(nb_bits - 1, -1, -1):
60 value |= self.read_bit() << i
61 return value
62
63
64 cpdef write_bit(BitStream self, bit):
65 if self.bits == 8:
66 self.io.write(chr(self.byte))
67 self.bits = 0
68 self.byte = 0
69 self.byte &= ~(1 << (7 - self.bits))
70 self.byte |= bit << (7 - self.bits)
71 self.bits += 1
72
73
74 def write(BitStream self, bits, nb_bits):
75 for i in range(nb_bits):
76 self.write_bit(bits >> (nb_bits - 1 - i) & 0x01)
77
78
79 def flush(BitStream self):
80 self.io.write(chr(self.byte))
81 self.bits = 0
82 self.byte = 0
83 self.io.flush()
84